Hot-air furnace for domestic use



` Nov. 2,2, 1966 M. PACKARD 2,961,220

How-AIR FURNACE FOR DOMESTIC USE Filed Sept. 10, 1957 2 Sheets-Sheet 1 A1. L ATTORNEYS.

NOV 22, 1950 v M. PACKARD 2,961,220

HOT-AIR FURNACE FOR DOMESTIC USE (bi-lob Mall pac/fard m/W www A TTORNEYS.

Unitecl States Patent Utilice 2,961,220 Patented Nov. 22, 1960 HOT-AIR FURNACE FOR DOMESTIC USE Mall Packard, 76 Willett Ave., Riverside 15, RJ.

Filed Sept. 10, 1957, Ser. No. 683,033

2 Claims. (Cl. 257-171) This invention relates to a hot-air furnace for domestic use.

Hot-air furnaces of the above character are well known in the art. Such furnaces of which I am familiar, however, have some heat exchange means which are more or less constructed as integral parts of the furnace and -which do not allow the removal of the heat exchange means as a unit short of dismantling of the furnace. It is desirable to provide a heat exchange unit for a hot-air furnace which is so constructed as to have at least a section thereof readily removable to allow ready modification of the said unit in a manner to discontinue the use of the heat exchange unit. Also, when it is desired to use an identical heat exchange unit as an attachment in the stack of a hot water or steam boiler, the fact that the heat exchange unit is removable allows continuous use of the hot water or steam boiler during the summer season for providing only a source of domestic hot water from usual devices without the necessity for completely removing such a unit from the boiler stack.

An object of the invention is to provide a hot air exchange unit so constructed as to have an interchangeable section.

Another object of the invention is to provide a hot-air furnace so constructed as to provide for a recirculation of the combustion gases in heat exchange relation with the air to be heated.

Another object of the invention is to provide a twopart heat exchange unit removably secured to each other in a manner to effectively seal the leakage of combustion gases between the meeting surfaces of the sections.

With these and other objects in view, the invention consists of certain novel features of construction as will be more fully described and particularly pointed out in the appended claims.

In the accompanying drawings:

Fig. l is a side elevation view of a hot air furnace embodying my invention;

Fig. 2 is a sectional view taken substantially along line 2-2 of Fig. l;

Fig. 3 is a top plan view of one of the sections of the heat exchange unit of the furnace;

Fig. 4 is a sectional view taken substantially along line 4-4 of Fig. 3;

Fig. 5 is a section view taken substantially along line 5-5 of Fig. 3;

Fig. 6 is a sectional view taken substantially along line 6--6 of Fig. 4;

Fig. 7 is an elevational section view of the other section of the heat exchange unit of the furnace;

Fig. 8 is a `front elevational view of the section shown in Fig. 7 looking from the left of Fig. 7 in the direction of ythe arrows on line 8 8; and

Fig. 9 is a fragmentary portion of the heat exchange unit looking at the front side thereof.

Referring to Fig. l, 10 designates generally an air heating apparatus or furnace for domestic use. Various known parts and details which are not essential for the description have been omitted since the invention as described will be clearly understood by those skilled in the art. The furnace comprises a sheet metal casing or jacket 11 having compartments or chambers 12 and 13 separated by a vertical wall 14. The oor of chamber 12 is formed by a horizontal wall 15 and provides a third chamber 16 in which there is provided a fire pot 17 constructed in the known manner of suitable material, so as to accommodate a fuel burner 18 of any approved manufacture and suitable for a furnace of the above character.

A heat exchange unit designated generally 20 is mounted within chamber 12 and is provided with an outlet ue 21 which opens to atmosphere and the draft therethrough being controlled in the known manner, not shown. The unit 20 is open to the passage of the combustion gases and is provided with a multiplicity of tubes which are positioned to cause the combustion gases to ow around the `tubes in tortuous paths in the travel of the gases from the combustion chamber to the ue outlet 21. Some of the combustion gases are recirculated through the unit by a motor operated blower 23 (see Fig. 2) which is mounted on the upper wall of unit 20 with the suction side of the blower connected to an opening 24 in the said upper wall so as to draw combustion gases from within the unit and to discharge the same under pressure into a conduit 25 which leads through an opening 26 into a chamber 27 located at the lower end of unit 20. The gases pass out of chamber 27 through openings 28 in the upper wall of chamber 27 to again be passed about said tubes 22.

The tubes 22 are sealed to the passage of combustion gases therethrough, as will be more fully described, and are open at one end thereof into chamber 12, the other end thereof opening into chamber 13 through an opening 29 in the wall 14. A duct 30 surrounds opening 29 in sealed relation at the marginal edges thereof and is connected to the discharge side of a motor driven blower 31 which is of much greater capacity than blower 23. Air drawn into chamber 13 through suction of blower 31 enters chamber 13 through a return duct 32 located in the top wall of chamber 13 and passes therethrough to a filter 33 which extends generally horizontal across the chamber 13 at a location above the duct 30. Air enters the blower 31 and is discharged under lpressure into duct 30 and ilows through tubes 22 into chamber 12 and out through duct 34 located in the top wall of chamber 12. It will be understood the duct 34 will be connected to the heat supply ducts of the heating system and the return ducts of the system will be connected to the duct 32 in the usual manner. It may be here mentioned that the unit 20 is considerably smaller than chamber 412 which provides a space in chamber 12 in which the ue conduit 21' extends in heat exchange relation with air` passing through chamber 12. A humidier 35 of known manufacture may be provided, in chamber 12.

The heat exchange unit 20 is constructed in :two separate sections 40 and 41 (see Figs. 3 to 8). The section 40 comprises a sheet metal casing which is generally rectangular and having vertical walls 42, 43, 44, 45 and top and bottom horizontally extending walls 46 and 47 providing a heat exchange chamber 40'. For purpose of description and orientation, wall 42 will be considered as being the front wall of section 40. This wall 42 has a rectangular opening 48 which is of a size nearly equal to outline size of wall 42. A ange 49 extends about opening 48 and projects outwardly of the wall. The wall 44, which may be termed the back wall, is likeinside wall45' and the `recirculating fan opening 24 is i' located substantially centrally in the top wall 46. The uppcrwall of chamber 27 is formed by a plate 52 which has a large central opening 53 therethrough and the openings 28 extend through said plate as seen in Fig. 6. A circular wall 54 extends about opening 53 to project therefrom through anropening 55 in wall 47 and is secured at the edge of said opening as by a Welded connection. A circularl wall 56 projects outwardly from the bottom wall 47 andI is concentric with wall 54 and isvspaced therefrom arsubstantial distance so Yas to provide an annular recess into which the wall of the re pot. 17 `.extends (see Fig., 2).. Attached to the section 401s a, conduit ZSjWhich is generally rectangular in cross section and extendsalong the top wal-l 46 fromV adjacent the iopening v24Var1d thence along the side wall 43 to the lower end thereof where it opens into chamber 27. The upper end of theconduit is coupled to the blower 23 (see Fig. 2).Y lThe section 40 is positioned within chamber 12 to besupported by Wall 15 and to engage againstvwalllf/,and maybe secured to these walls in any.appropriate manner, not shown. V

The section y41v (Figs. 7 and S) 'comprises vertically extending sheet-metal plates or walls 57and158 which .are adapted to close openings 4S and 50. These walls 57,553 are .each provided with asimilar plurality of equal spaced openings 59,160 therethrough which vextend in line with eachA other and are adapted` to receive tubes. YA plurality of tubes 22Vextend in parallel fromv one wall to the other in general horizontal `direction with air tight joints at the edges of the openings. The wall 57` has a ange 61 extending inwardly about the periphery thereof and fastening lugs 62-extend from said ange. For convenience inthe handling of section 41, handles 63 are attached to wall' 57, which may be considered asv being the front of section 41. The wall 58 is likemanner of a anged closure. vIt will also be apparent that section 41 is removably .received within section 4G. Thus during the summer months the section 41 may be removed and replaced with a unit section (not shown) which may comprise two spaced wall sections similar to walls 57 and 58 but omittting the openings S9, 60 therethrough so as to effectively seal oli the openings 48, 50

Y of section 40.

The sections 40, 41, if removed from the complete enclosure as shown in Fig. 1, will appear as a unitV substantially as shown in Figure 2. In this form, the sections become a heatexchanger that lis usable in such applications as recovery units for the heat lost up a furnace stack. To this end, the furnace flue flange may be coupled to wall 54 by suitable sheet metal piping and the hue continued to the chimney by connecting to outlet 21. return ductcontainingfa -fan'and the supply ducting to frange 49. In this particular application the section 41 isreplaced by `.the unit section mentioned above to allow`7the.'furnace toY remain in operation for providing hotwaterand no heat during the summer months.

flclair'nr.v Y

11.- In .a hot-air furnace,a casing having air inlet and outlet passageways and an access opening closed by a door, a'heat exchange chamber within saidr casing and accessible through said door, said chamber having opposite walls with openings therein of different size and `wise provided with a flange 64 which extends about the periphery of the wall. l f

yThe section 41 is receivedwithin the chamber 40 of section 4@ (see Fig l) with the wall 57 abutting against the outer edge oftlange49 and with the ange 61 snugly received over ange V49 with air tight relation. The wall 58 and llange 64 thereof has similar engagements with the ilange 5?. and similarly forms va seal against the cscape orr combustion gases into chamber 12 and duct 30. The sections k40, 41 are secured to each other by clamp bolts 65 (see Fig. 9) which extend through lugs 62 and threadingly engage the wall 48. The chambers 12 and 16 have openings 66, 67 thereto which are normally closed by a door 68, and chamber 13 also has an, opening thereto which is normally closed by a door @indicated in broken lines. The door openings are of a size to allow the passing therethrough of the parts of the furnace mounted within the said chamber.

From the foregoing, it will be apparent that I have disclosed an air heating furnace so constructed'that the heat exchange unit section v41 is removably received Within section 40 in sealed relation therewith in the through which openings air may circulate from said casing inlet -toV said casing outlet passageways, the Wall with the .larger opening being oppositeA said door and accessible therethrough, each of said wall openings being provided withl a surrounding ange, a removable unit comprising a closure wall for each of said openings, the smaller closure wall being of a size to pass through the larger opening, open ended air passage tubes connecting and extending through said closure walls for the passage of air from the inlet to the outlet passageway, each closure wall of said unit having a flange, the flanges of said openings and the anges of the closurewalls tele-V scoping to support said unit and to exclude the passage Vof air throughv the junction of said closure, whereby said unit may be removed in a direction from the smaller opening toward the larger opening.

2. In a hot air furnace as in claim 1 wherein said flanges about said openings in the opposite walls extend in .the same Vdirection from` said walls and said closure walls are connected to provide a unit spacing the closure walls substantially the distance that said opposite walls are spaced, so that the ianges of both closure walls and the anges about the both openings which they close may be simultaneously telescoped.

References Cited in the le of ythis patent UNITED STATES PATENTS 2,674,240 Etheredge Y Apr. 6, 1954 Opening 2.9 may then be connected to a 

